A sub-circuit extraction, which is a special form of the sub-graph isomorphism problem in graph theory, is identification of instances of a pattern circuit in a large circuit schematic. The sub-circuit extraction may be done by checking presence of the pattern circuit in the large circuit schematic. However, the sub-circuit extraction may not be a straightforward comparison of devices or components present in the pattern circuit to their counterpart devices or components in the large circuit schematic. That is, the connectivity between the counterpart devices or components in the large circuit schematic has to topologically match the connectivity of the devices or components in the pattern circuit. Additionally, the computational complexity for the extraction scheme may grow significantly as the size of the pattern circuit or the large circuit schematic increases.